The invention relates to a generator circuit in an integrated semiconductor circuit for generating a clock voltage, which has a voltage that is raised with respect to a supply potential of the generator circuit.
Generator circuits of this generic type are used, for instance, in integrated semiconductor memories, especially DRAMs, as so-called word line voltage generators. The purpose of such generator circuits in DRAMs, for instance, is to make a clock voltage available which is higher than the supply voltage of the entire circuit configuration, by at least the amount of the threshold voltage of the selection transistors of the memory cells. Typically, this clock voltage is raised by the amount of one-half the supply voltage. For instance, this makes it possible to write-in a logical 1 as data to be stored in a selected memory cell at its full voltage level, or in other words not after having been reduced, for instance, by the amount of the aforementioned threshold voltage.
For instance, two series-connected n-channel transistors have heretofore been used for this purpose. However, such a circuit requires doubly raised voltages, as will be explained below. These voltages carry the danger of voltage breakdown and damage to the semiconductor material.